# DC_LockdownRange

## C Specification

      #include <nitro/os.h>

      void DC_LockdownRange(
                  void*   startAddr ,
                  u32     nBytes );

## Description

Locks and discards the contents of the data cache that is hit by the specified region

As a result of this function, the usable area of cache decreases and the miss rate could increase.

`startAddr` is rounded down to the closest 32-byte boundary. `startAddr` + `nBytes` is rounded up to the closest 32-byte boundary.

## Internal Operation

Operates registers 7 and 9 of the system control coprocessor.

## Arguments

`startAddr` | Lowest address in the region to be locked down
`nBytes` | Number of bytes of the region to be locked down

## Return Values

None.

## See Also

`DC_TouchRange
`

## Revision History

12/22/2003 Initial Version